气象观测中,常用经纬仪跟踪随风飘移的氢气球,实现对于空中各高度上风场的观测。使用单经纬仪进行空中风观测时,往往存在一定误差,主要来源于两个方面,一是受限于观测数据的低可靠性以及氢气球升速的变化,所求空中风具有较大的误差；二是氢气球自身具有一定的惯性和曳力,使其本身不能作为风场的良好示踪物,所观测速度不能直接代表空中风速度。本文基于单经纬仪风场观测原理,提出多经纬仪定位方法(Multi Theodolite Location Method,MTLM)。首先将经纬仪协同探测氢气球获得的高度角和方位角信息,通过相应的坐标变换与最小二乘法算法,获取氢气球的精确轨迹和速度信息,随后对运动方程分析,实现了由氢气球速度对于背景风场速度的反演。在仿真实验中,本文方法定位的氢气球空中轨迹,各方向均方根误差小于2m；反演背景风速时,通过本方法反演的背景风场与传统单经纬仪相比,水平速度和垂直速度准确度分别提升超过80和90。外场实验中,采用MTLM方法反演水平风速较单经纬仪性能有较大的提升,风向和风速准确度分别提升86和66,在高精度风速获取上MTLM方法具有更好的性能。
In the field of meteorological observation,theodolite is commonly used to track the wind drifting hydrogen balloon to realize the detection of wind direction and speed at all heights.When only a single theodolite is used,there are usually some errors,which mainly come from two aspects:one is limited by the low reliability of the detection data and the change of the speed of the hydrogen balloon,so the wind obtained has a large error；second,the hydrogen balloon itself has a certain inertia and drag force,so that it cannot be used as a good tracer of wind field,and the observed speed can’t directly represent the wind speed.Based on the principle of wind field observation with a single theodolite,a multi theodolite location method(Multi Theodolite Location Method,MTLM)to achieve accurate locating of the hydrogen balloon is proposed in this paper.Firstly,the altitude and azimuth angles information obtained by theodolite cooperative detection of hydrogen balloon are used to obtain the accurate trajectory and velocity information through the corresponding coordinate transformation and least square algorithm.Then,the motion equation of the hydrogen balloon is analyzed,and the velocity of the background wind field is retrieved from the velocity of the hydrogen balloon.In the simulation,the root mean square error is less than 2 m,and this method can improve by more than 80% and 90% in horizontal and vertical velocity retrieval respectively.In the field experiment,this method can improve the accuracy of wind direction and velocity estimates by more than 86% and 66% compared with the traditional single theodolite method.The MTLM method has better performances in the acquisition of high precision wind speed.
ZHOU Jie, GAO Hang, LIU Jin-bo, YANG Wei-wei, LI Jian-bing. A wind retrieving method based on tracking the balloon with multiple theodolites[J]. LASER & INFRARED,2022,52(7):1022~1031